1. Field of the Invention
The present invention relates to a yaw-rate sensor.
2. Description of Related Art
Linearly oscillating yaw-rate sensors are generally known. In these yaw-rate sensors, parts of the sensor structure are actively set into oscillation (primary oscillation) in one direction, i.e., along a first axis (x-axis) that is oriented parallel to a substrate surface. In response to an external yaw rate about one particular sensitive axis, Coriolis forces act on the oscillating parts of the sensor structure. These Coriolis forces, which vary periodically with the frequency of the primary oscillation, induce oscillations in parts of the sensor structure (secondary oscillation) in the direction of a second axis that is oriented perpendicularly to the x-axis. The second axis can be oriented parallel to the substrate surface or perpendicularly to the substrate surface. Detection means, which capacitively sense the secondary oscillation via electrodes, are mounted on the sensor structure.
To an increasing degree, applications demand yaw-rate sensors that are capable of detecting yaw rates about a plurality of mutually perpendicularly extending axes. Till now, this has been accomplished by placing a plurality of monoaxial sensors laterally or vertically side-by-side. However, in terms of costs, space requirements, power requirements, and the relative orientation accuracy of the axes, there are disadvantages entailed in using a plurality of monoaxial yaw-rate sensors.
Furthermore, biaxial yaw-rate sensors are known from the related art which are capable of detecting yaw rates about two mutually perpendicularly extending axes that are oriented parallel to the substrate surface.